Metadata Plus

12 min

MDP lets you extend any system object with a series of meta-fields. It is similar to object-oriented programming. For example, in object-oriented programming, you can create a base Order class, and then a Purchase Order Type object called PurchaseOrder, which inherits its properties and adds specific fields.

The root meta-class is based on a database table called system meta-class. Consider that an abstract meta-class which you must extend to use when associating extended new attributes with a new meta-class. Order becomes a system meta-class, and PurchaseOrder becomes a meta-class that you can extend.

The instance of the meta-class that holds values is called meta-object.

Name	Description
Binary	MSSQL Common Type
Bit	MSSQL Common Type
Char	MSSQL Common Type
DateTime	MSSQL Common Type
Decimal	MSSQL Common Type
Float	MSSQL Common Type
Image	MSSQL Common Type
Int	MSSQL Common Type
Money	MSSQL Common Type
NChar	MSSQL Common Type
NText	MSSQL Common Type
NVarChar	MSSQL Common Type
Real	MSSQL Common Type
UniqueIdentifier	MSSQL Common Type
SmallDateTime	MSSQL Common Type
SmallInt	MSSQL Common Type
SmallMoney	MSSQL Common Type
Text	MSSQL Common Type
Timestamp	MSSQL Common Type
TinyInt	MSSQL Common Type
VarBinary	MSSQL Common Type
VarChar	MSSQL Common Type
Variant	MSSQL Common Type
Numeric	MSSQL Common Type
Sysname	MSSQL Common Type
Integer	Metadata Type
Boolean	Metadata Type
Date	Metadata Type
Email	Metadata Type
URL	Metadata Type
ShortString	Metadata Type
LongString	Metadata Type
LongHtmlString	Metadata Type
DictionarySingleValue	Metadata Type
DictionaryMultiValue	Metadata Type
EnumSingleValue	Metadata Type
EnumMultiValue	Metadata Type
StringDictionary	Metadata Type
File	Metadata Type
ImageFile	Metadata Type
MetaObject	Metadata Type

Not all properties have a visual designer associated with them, but you can use all of them to extend the meta-class.

The MDP is designed to give the resulting database structure the fastest performance. When a meta-class is created, the container data table and history tables are created with a corresponding set of stored procedures and full text indexes (if full text functionality is enabled). The appropriate indexes are also put.

Meta-fields and Meta-classes

Meta-fields

Meta-fields describe different properties associated with an element inside Optimizely Customized Commerce. You can create a meta-field of any type supported by Metadata Plus.

Meta-classes

Customized Commerce uses meta-classes to describe different types of elements, such as Categories and Products, that are used in the creation and extension of the Customized Commerce solutions developed. Meta-class is a collection of meta-fields. The following types of meta-classes are defined:

Mediachase.MetaDataPlus.System. Used for the built-in OrderGroup elements of Customized Commerce.

Mediachase.MetaDataPlus.User. Created when a user defines a new meta-class for a OrderGroup. It is always an extension of one the existing System meta-classes.

Use meta-classes and meta-fields

It is important to understand the concepts of a meta-class and meta-field, which form the basis for purchase orders and subscriptions, to fully understand how they work within Optimizely Customized Commerce. For a better understanding, consider an example of creating a new order type WorkOrder which has the following properties:

Hours

Matrials

FinalPrice

To duplicate this product inside your solution, create a WorkOrder meta-class with the OrderGroup meta-class as its parent. In this example, WorkOrder is of type Mediachase.MetaDataPlus.User, and the built-in OrderGroup meta-class is of type Mediachase.MetaDataPlus.System.

Next, assign the properties to your WorkOrderClass by creating a meta-attribute for each Property, then assigning them to your WorkOrderClass. For example, the Hours property could be a meta-attribute of type Integer, and FinalPrice can be a meta-attribute of type money. After you create these meta-attributes, assign them to your WorkOrderClass.

Create meta-fields

Mediachase.MetaDataPlus.Configurator.MetaField.Create(context: OrderContext.MetaDataContext,
        metaNamespace: "Mediachase.Commerce.Orders.User",
        name: "BidPrice",
        friendlyName: "Bid price",
        description: "Bid Price",
        dataType: MetaDataType.Decimal,
        length: 17,
        allowNulls: true,
        multiLanguageValue: false,
        allowSearch: false,
        isEncrypted: false)

Update meta-fields

var metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Load(OrderContext.MetaDataContext, "BidPrice");
    metaField.Description = "Better desciption";
    metaField.OnUpdated();

Delete meta-fields

var metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Load(OrderContext.MetaDataContext, "BidPrice");
    Mediachase.MetaDataPlus.Configurator.MetaField.Delete(OrderContext.MetaDataContext, metaField.Id);

Create meta-classes

var orderGroupClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "OrderGroup");
    var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Create(OrderContext.MetaDataContext, "WorkOrder", "Work Order", "WorkOrder", orderGroupClass, false, "Work Order" );

Update meta-classes

var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder");
    metaClass.FriendlyName = "Work order change";

Delete meta-classes

var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder");
    Mediachase.MetaDataPlus.Configurator.MetaClass.Delete(OrderContext.MetaDataContext, metaClass.Id);

Add meta-felds to meta-classes

var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder");
    var metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Load(OrderContext.MetaDataContext, "BidPrice") ?? Mediachase.MetaDataPlus.Configurator.MetaField.Create(
        context: OrderContext.MetaDataContext,
        metaNamespace: metaClass.Namespace,
        name: "BidPrice",
        friendlyName: "Bid Price",
        description: "Bid Price",
        dataType: MetaDataType.Decimal,
        length: 17,
        allowNulls: true,
        multiLanguageValue: false,
        allowSearch: false,
        isEncrypted: false);
    
    if (metaClass.MetaFields.All(x => x.Id != metaField.Id))
    {
        metaClass.AddField(metaField);
    }
    else if (!metaField.DataType.Equals(MetaDataType.Decimal))
    {
        metaClass.DeleteField(metaField.Name);
        Mediachase.MetaDataPlus.Configurator.MetaField.Delete(OrderContext.MetaDataContext, metaField.Id);
        metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Create(context: OrderContext.MetaDataContext,
            metaNamespace: metaClass.Namespace,
            name: "BidPrice",
            friendlyName: "Bid Price",
            description: "Bid Price",
            dataType: MetaDataType.Decimal,
            length: 17,
            allowNulls: true,
            multiLanguageValue: false,
            allowSearch: false,
            isEncrypted: false);
        metaClass.AddField(metaField);
    }

Remove meta-fields from meta-classes

var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder");
    metaClass.DeleteField("BidPrice");